The Biosolar house was completed in 2017 for Christine Völker and Thomas Grasenack in Carterton, Wairarapa.

Christine and Thomas’s delightful home is a perfect example of the mix of Andi’s European expertise and Kiwi experience.

That combination created a house that’s suited to the idyllic countryside location, staying warm in winter and cool in summer.

The project had several key components. The building had to:

  • Be sustainable and have minimal ecological impact
  • Be draught-proof and extremely well insulated, to minimise energy requirements for heating or cooling
  • Have excellent detail solutions, so the larger goals were reflected in all the smaller touches and finishes
  • Come in on budget.

To achieve these goals, the project had a strong teamwork focus.

Andi worked closely with Christine and Thomas to plan their dream home, and provided transparent quoting and invoicing.

He managed the process from design to move in, ensuring that the team philosophy kept everyone engaged and happy at every step of the journey.

Read on to see how that journey unfolded!

CAD drawings

While Andi loves building, his true passion is design, and his skills in specialist CAD (Computer Aided Design) software allow him to explore and experiment to bring his client’s project to virtual life.

As with many fields, having a very clear shared vision at the planning stage means the expensive production stage can proceed as smoothly and cost-effectively as possible.

Behind the CAD software’s pretty pictures is a listing of every single component that will be required in the construction.

The 3D draft is converted into 2D plans, providing a detailed inventory and comprehensive quantity list for the prefabrication of all the different parts.

This blueprint provides the master plan for efficient prefabrication and ensures that everything will fit together perfectly when the rapid on-site build commences.


Wherever possible, non-treated timber, wool insulation, screws rather than adhesives, and other non-toxic sustainable materials are used.

Timber is sourced from smaller sawmills, with Andi and Thomas viewing the raw product before it’s delivered on site for prefab preparation.


Almost every piece of the construction will be precut according to the CAD-generated inventory. Each piece also gets its own project number allocated.

Those numbers are shown on the 2D construction plans, giving a guide for fitting together all the components in the wall frames, ceiling elements, roof sections and so on.


Each element is assembled according to the construction plans.

Walls are insulated with wool, lined with soft wood fibre-board for further insulation, weatherproofed and covered with OSB (Oscillated Strand Board) or cellulose GIB board for bracing and draft-proofing.

All services like electricity, heating and plumbing are run in an installation cavity inside the wall so that there is no need to cut or drill the vapour- and draft-proof building core.

The work platform is on wheels, so any prefab section being worked on when rain threatens it can be easily moved under cover, allowing lining to continue!

After finishing, the assembled elements are fitted with special hooks for craning and stored under cover in preparation for the three-day build.

Tracking Plates

A vital stage is the installation of the u-shaped tracking plates. These are laid out to precisely define the geometry of the house and make sure walls are placed exactly where they need to be.

Prefabrication allows for a very efficient build, but the tracking plates need to be highly accurate- they have a maximum tolerance of 2mm over 10 lineal meters!

With all the elements in place, it’s time to…